Select 'Bulky' and the Product Group you created in Step 2 from the drop downs.

Go to the Dashboard and click 'Upload to TheMarket'

To check that the product(s) have the Bulky charge applied you can check in TheMarket admin. Go to 'Products - Products'. Click on the product name to see the full product details. Scroll down to the Product Description section and check that the 'Bulky' check box is ticked.